All rechargeable batteries used in mobile devices become less effective over time. Certain temperature conditions can also cause a battery to age faster.

In this file photo, people wait to buy the Apple iPhone 6 and 6 Plus devices outside an Apple store in Hong Kong, Sept. 19, 2014.

Apple said these older batteries could unexpectedly shut down during times of high energy demand. It called such shutdowns "unacceptable" and said that is why the company took "power management" measures to prevent them.

Many people have long suspected Apple intentionally slows the performance of older iPhones in an effort to get users to buy new ones. Apple has strongly denied this suspicion.

"We have never - and would never - do anything to intentionally shorten the life of any Apple product, or degrade the user experience to drive customer upgrades," the company said.

Despite this explanation, Apple was criticized for not informing iPhone owners about the power issues before it decided to slow devices down. Many owners argued they would have chosen to replace batteries if they had known the issues beforehand.

Several lawsuits seeking monetary damages from Apple were also started by iPhone owners. They owners argued they would not have spent money on new iPhones if they had known there were other ways to fix slow performance.

In a statement Wednesday, Apple said it had received requests for information about the issue from U.S. government agencies. The statement followed a Bloomberg report that the Department of Justice and Securities and Exchange Commission were looking at whether the company's actions had violated any securities laws.

To answer user concerns, Apple announced it was offering owners of an iPhone 6 or later the chance to replace batteries at a reduced cost. The price to replace a battery was cut from $79 to $29, with the deal available worldwide through December 2018.

In its announcement about the iOS 11.3 update, the company said users themselves will be able to turn off the power management feature. In addition, a new tool will be added to show iPhone battery health and suggest when service is needed.

Apple also previewed some other new features to be released with its iOS 11.3 update this spring.

The update will include several new Animojis. These are animated characters iPhone X owners can use with their voices and facial expressions to create videos and messages.

In addition, a new feature in the iOS Health app is designed to organize user data from various medical facilities in one view. The Health Records feature can also be used to send messages to patients about conditions, medicines and laboratory results. Apple says all medical data is encrypted for user protection.

The iOS 11.3 update also includes a change to Apple Music the company says makes it easier to play unlimited music videos without seeing advertisements. Also, Apple News will include new features to find and view the most important videos of the day. Finally, a new tool called Business Chat will provide a way for users to directly connect with company help representatives from within the Messages service.

I'm Bryan Lynn.

Bryan Lynn wrote this story for VOA Learning English. Hai Do was the editor.

We want to hear from you. Write to us in the Comments section, and visit 51VOA.COM.

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Words in This Story

degrade – v. to damage the quality or condition of something

upgrade – n. a situation in which one thing is replaced by something better, newer, more valuable, etc.

feature – n. an interesting part or characteristic of something

animated – adj. produced by the creation of a series of drawings, pictures, etc.

encrypted – v. to change electronic information into a secret system of letters, numbers, or symbols to hide its meaning